Repotting Phals - pot size
 

Hi!
I have two young phals that have quite healthy root balls, each in a 12cm (4,7 inches) pot.
I will be repotting them soon, and have been wondering whether to repot into a 15cm (5,9) or a 17cm (6,7 inches) pot.
The 15cm seems more reasonable at first, specially since the plastic nursery pots are quite cheap, but the "outside pot" is a bit more expensive, so I would want to buy a size that is going to last more than a few months.

I live in a dry climate right now (Madrid), so root rot is less common than dehydration for my plants in general.

In your experience, do average phals do well in 15 cm pots for a long time? Are larger pots (17cm +) usually needed or is it more an exception than a normal thing? What pot size do you have most of your phals in?

Hello Lauchi
As a norm, the next suitable pot size would be the one that will allow plant growth for the next two years.
In this case, 15 cm might be ok but it would be useful if you post some pics of the plants.

As a side note, I have some Phals in 15 cm pots but to avoid the center to be wet for a long time I'm using really large bark + LECA (to create large voids inside the medium) together with a mix of water retentive materials such as perlite or coco chips (to give moist).

Thanks for your reply :D

I've tried attaching one pic, I don't know if you can clearly see it as they grew some algae from the greenhouse. Now I've cut back the watering significantly.

The one in the left is more rootbound. It's not dramatic or anything, but I want them to have space to grow in the summer

When using bark I use the smallest pot into which I can fit the roots when I twist them into the pot. I don't know what that will be until I unpot the plant.

The plants seem OK. I have at least two that are even worse than yours and they are doing great.
I think they can be in those pots at least one more year but if you repot now it won't be any problem.
Your climate is similar to mine so I think my "medium recipe" will work.

Great! I will try to find some LECA and if I can't I''ll put largest bark chunks I can to create that space you talk about between the roots. And I have quite a bit of perlite and sphagnum moss around so I'll add those for water retention.

The other reason I wanted to repot them was to put new medium due to the algae and older medium (about 1-2 years old right now)

If they aren't that crowded and you have orchids that are doing well with way more roots then I'll just go one size up instead of two so I don't overpot them.

Thank you so much!!

It depends on your conditions but I'm not a fan of sphagnum with Phals.
Don't forget that new bark is hydrophobic so you must increase watering during the first months (which will not be a problem considering Madrid in summer :biggrin:).

Hi Lauchi :waving

I agree with rbarata. For me personally, in my UK climate and conditions, Spagnum is too water retentive. My Phals are all in med grade bark only and are very happy and healthy this way.

If your plants are in 12cm pots currently, I wouldn't expect you to need larger than a 15cm pot now, or for several years - if ever!

What do you find the main issue to be with sphagnum? Is it that it retains too much water or that it breaks down too soon or is a insect breeding spot something like that?

If it's regarding water retention, I'm having the opposite issue with it right now: my moss poles for my monstera adansoniis are drying ultra fast (to the point where I put them inside the shower to soak and they are completely dry in two days, with absolutely no use of trying to mist them to keep them humid and being surrounded by plastic on half of the pole) and the orchids I have in the bark/sphagnum mix right now are lasting less than a week moist even though we've been having colder weather right now and I water by soaking for about 20 mins

The ideal potting medium is different for different conditions - what's important is what you're trying to achieve... humid air (not soggy wet) in the root zone. So it depends on YOUR situation.. humidity, how often you want to water. Bark tends to dry faster than sphagnum. You almost can't overwater in bark. But most people need to water every few days. Sphagnum stays wet longer. So that's good or bad depending on your situation. With enough humidity - and likely daily watering, Phals can be very happy mounted - but for most people that's hard, even impossible, to sustain unless growing in a greenhouse. . So figure out your objective, and pot accordingly. There is no one "right answer",

I never know what size I will be using till after it's unspotted. I use bark and keep my plants in a pot where about 75% of it is filled with the roots. Sometimes I use packing peanuts in the bottom. It really all depends on you growing conditions and watering habits.